Deepwater containment system and method of using same background

ABSTRACT

An oil and gas collection system, comprising a source of oil and gas flowing into a body of water; a collector located adjacent the source of oil and gas; a riser to transport the oil and gas towards a surface of the body of water, a first end of the riser fluidly connected to the collector; and a separator fluidly connected to a second end of the riser, the separator adapted to separate the oil and gas into a first oil rich stream and a second gas rich stream, the separator comprising an oil rich stream outlet and a gas rich stream outlet. In some embodiments, the source of oil and gas comprises a blow out preventer.

This application claims the benefit of U.S. Provisional Application No.61/376,542 filed Aug. 24, 2010, the entire disclosure of which is herebyincorporated by reference.

BACKGROUND

When oil and gas is spilled into the sea, for example from a leakingtanker ship, a leaking pipeline, from oil seeping from an undergroundformation, or from oil flowing from a subsea wellhead or blowoutpreventer, there is a desire to collect the oil and gas and contain andtransport or otherwise dispose of the oil and gas to preventenvironmental damage to the sea and nearby coastlines. Various systemsand methods of collecting spilled oil and gas are known in the art andset forth below:

U.S. Pat. No. 4,405,258 discloses a method for storing alighter-than-water fluid, e.g., oil, produced from the blowout of anoffshore subsea well. The method includes the steps of deploying acontainment dome in shallow water near the location of the seabed wherethe containment dome is to be located. The containment dome as an upperexpanded dome-like fluid impervious membrane, a fluid impervious hollowperipheral ring attached to the periphery of the membrane to provide adepending bag-like container, and discrete water drainage means withinthe bag-like container for connection to pump conduit means therefrom.Wet sand from the seabed is then pumped into the bag-like container, andwater is then drained from the wet sand through the water drainage meansso as to provide a body of drained sand disposed within the bag-likecontainer and providing a hollow peripheral ring as a hollow peripheraltorus acting as a self-supporting structure and as an anchor for thedome-like structural unit. The dome is then charged with a buoyantamount of air and the buoyed dome is floated out to the site where thedome is to be deployed. It is then submerged by controllably releasingthe air while substantially simultaneously filling the dome with water,thereby sinking the dome until the lighter-than-water fluid is capturedwithin the dome, while such fluid substantially simultaneously displaceswater from within the dome. U.S. Pat. No. 4,405,258 is hereinincorporated by reference in its entirety.

U.S. Pat. No. 4,643,612 discloses an oil storage barge having a concavebottom is adapted to be anchored over a subsea well or pipeline that isleaking oil. Flexible skirts extend to the ocean floor, and oil that istrapped under the barge may be stored in the barge or then transferredto another vessel. U.S. Pat. No. 4,643,612 is herein incorporated byreference in its entirety.

U.S. Pat. No. 5,114,273 discloses a protective device installed to oraround an offshore drilling platform for oil or gas and the device whenin operation to encircle or enclose the platform with a floatingcontainment device and attached oil containment curtain hanging from thedevice to the ocean floor. The pollution containment device to besubmerged normally and activated to the surface when needed. This devicewill entrap offshore platform pollutants in a short amount of time witha minimum amount of effort and will maintain a clean environment. Othermethods of offshore platform pollution containment devices are shown,including permanent non-moving oil pollution containment barriers andactivated barriers that operate internally and externally of the oilplatform to form an all encompassing barrier from the ocean floor toabove the water surface to hold an oil spill to the platform area. U.S.Pat. No. 5,114,273 is herein incorporated by reference in its entirety.

U.S. Pat. No. 5,213,444 discloses an oil/gas collector/separator forrecovery of oil leaking, for example, from an offshore or underwater oilwell. The separator is floated over the point of the leak and tetheredin place so as to receive oil/gas floating, or forced under pressure,toward the water surface from either a broken or leaking oil wellcasing, line, or sunken ship. The separator is provided with adownwardly extending skirt to contain the oil/gas which floats or isforced upward into a dome wherein the gas is separated from theoil/water, with the gas being flared (burned) at the top of the dome,and the oil is separated from water and pumped to a point of use. Sincethe density of oil is less than that of water it can be easily separatedfrom any water entering the dome. U.S. Pat. No. 5,213,444 is hereinincorporated by reference in its entirety.

U.S. Pat. No. 6,592,299 discloses a method of detecting and locatingfresh water springs at sea essentially by taking salinity measurementsand by methods and installations for collecting the fresh water. Thecollection installations comprise an immersed bell-shaped reservoircontaining and trapping the fresh water in its top portion, and apumping system for taking fresh water and delivering the fresh water viaa delivery pipe, characterized in that the circumference of the bottomend of the reservoir and/or the circumference of the bottom end of achimney inside the reservoir and open at its top end and surrounding thefresh water resurgence in part and preferably in full, follow(s) closelythe outline of the relief of the bottom of the sea so as to provideleakproofing between the circumference(s) and the bottom of the sea.U.S. Pat. No. 6,592,299 is herein incorporated by reference in itsentirety. There is a need in the art for one or more of the following:

Improved systems and methods for collecting spilled oil and gas from amarine environment;

Improved systems and methods for collecting oil and gas spilling from asubsea well;

Improved systems and methods for collecting oil and gas spilling from asubsurface formation located beneath a body of water; and/or

Improved systems and methods for collecting oil and gas spilling from asubsurface formation located beneath a body of water, and then burningthe gas and containing the oil in a surface vessel.

SUMMARY OF THE INVENTION

One aspect of the invention provides an oil and gas collection system,comprising a source of oil and gas flowing into a body of water; acollector located adjacent the source of oil and gas; a riser totransport the oil and gas towards a surface of the body of water, afirst end of the riser fluidly connected to the collector; and aseparator fluidly connected to a second end of the riser, the separatoradapted to separate the oil and gas into a first oil rich stream and asecond gas rich stream, the separator comprising an oil rich streamoutlet and a gas rich stream outlet.

Another aspect of the invention provides a method comprising locating asource of oil and gas flowing into a body of water; collecting at leasta portion of the oil and gas; flowing the collected oil and gas to asurface of the body of water; separating at least a portion of the oilfrom the gas; flowing the portion of oil to a floating vessel; andburning at least a portion of the gas.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the features and advantages of the present invention can beunderstood in detail, a more particular description of the invention maybe had by reference to the embodiments thereof that are illustrated inthe appended drawings. These drawings are used to illustrate onlytypical embodiments of this invention, and are not to be consideredlimiting of its scope, for the invention may admit to other equallyeffective embodiments. The figures are not necessarily to scale andcertain features and certain views of the figures may be shownexaggerated in scale or in schematic in the interest of clarity andconciseness.

FIG. 1 is a schematic diagram depicting a wellsite positioned about asubsea reservoir, the wellsite having a containment system in accordancewith an aspect of the present invention.

FIG. 2 is a schematic diagram depicting a wellsite positioned about asubsea reservoir, the wellsite having a redundant containment system inaccordance with an aspect of the present invention.

FIG. 3A is a schematic diagram depicting a riser usable with thecontainment systems of FIGS. 1 and/or 2. FIG. 3B is a schematic view ofan integrated separator usable with the riser of FIG. 3A.

FIG. 4 is a flow chart depicting a method of deepwater containment.

DETAILED DESCRIPTION

Presently preferred embodiments of the invention are shown in theabove-identified figures and described in detail below. Embodiments aredescribed with reference to certain features and techniques forcontaining fluids released into the sea.

FIG. 1:

FIG. 1 is a schematic diagram depicting a wellsite 100 positioned abouta subsea reservoir 102. The wellsite 100 is provided with a containment101 for capturing fluids released into the sea 103. The wellsite 100includes a surface platform 104 floating on the sea 103, with a riser106 extending therebelow for receiving fluids generated from thereservoir 102. A subsea end of the riser 106 is secured to a suctionpile 108 positioned in the sea floor (or mud line) 110. Riser connector109 is provided to secure the riser 106 in position.

The wellsite 100 is further provided with a blow-out preventer (BOP) 112positioned at a top end of wellbore 114. The wellbore 114 extendsthrough the subsea floor 110 and into the reservoir 102. The BOP 112 isin fluid communication with the wellbore 114 for receiving the fluids(e.g., gas, hydrocarbons, water, etc.) from the reservoir 102. Amanifold 116 may optionally be fluidly connected between the BOP 112 andthe riser 106 to facilitate the flow of fluids therebetween. The riser106 may be, for example, a tubular member for passing fluid receivedfrom the BOP 112 and/or manifold 116 to the surface. A trap 117 isprovided at the subsea end of the riser to collect fluids and/or solids.A pump 118 may also be provided within riser 106 to selectively drawfluid from the BOP 112 through the riser 106. The manifold 116 and/orpump 118 may be used to manipulate the flow of fluid about the wellsite100.

Fluid drawn from the reservoir 102 and to the surface via riser 106 maybe stored in a surface collector 122. The surface collector 122 may be,for example, a separator that separates components of the fluid, such asgas and liquid, as will be described more fully herein. The portions ofthe fluid stored in the collector may optionally be removed, forexample, by burning the gas with a flare 124. Preferably, the pressureof the fluid is reduced in the collector 122. The remaining fluid may bepassed to a vessel 120 via tubing (or off-take line) 126 for transport.The tubing 126 preferably fluidly connects the collector 122 to thevessel 120 for establishing fluid communication therebetween.

From time to time, fluid from the reservoir 102 may escape into the sea103. For example, a wellsite leak 130 may allow fluid to escape from thewellsite system 100 and into the sea 103 as fluid is produced from thereservoir 102. In such cases, the containment system 101 may be employedto re-capture fluid released by one or more wellsite leaks 130. As shownin FIG. 1, the subsea containment system 101 includes subsea collector132 positionable about the leak(s). Additional subsea collectors 132could also be connected to manifold 116. The subsea collectors 132 maybe fluidly connected to riser 106 and/or manifold 116 via flowlines 134a-b for passing fluid thereto. The subsea collectors 132 are configuredto capture wellsite leaks 130 to prevent release of reservoir fluidsinto the sea 103 as will be described more fully herein.

In some embodiments, collector 132 may be a flange which is directlybolted and/or sealed to BOP 112.

In some embodiments, collector 132 may be a dome which is cemented inplace around BOP 112.

In some embodiments, collector 132 may be a dome which is sealed aroundthe BOP 112, and anchored to and sealed to the sea floor 110 withannular suction piles.

In some embodiments, collector 132 may be a dome which is sealed aroundthe BOP 112, by forcing the edges of the dome down into the sea floor110.

In some embodiments, collector 132 may be a dome which is not sealedaround the BOP 112, and which provides one or more areas of accessbetween the BOP 112 and the body of water 103.

In some embodiments, riser 106 may be connected directly to and locateddirectly above collector 132.

In some embodiments, collector 122 includes from about 1 to about 6separator vessels, for example from about 2 to about 4 vessels, forexample Gasunie separators.

FIG. 2:

FIG. 2 is a schematic diagram depicting a wellsite 200 positioned abouta subsea reservoir 202, the wellsite 200 having a redundant containmentsystem 201. The wellsite 200 of FIG. 2 includes a primary structure 200a and an optional secondary structure 200 b. The primary and secondarystructures 200 a,b each may have a buoyant riser 206 a,b, a suction pile208 a,b, a trap 217 a,b and a pump 218 a,b that may operate in the samemanner as the riser 106, the suction pile 108, trap 117 and the pump118, respectively, of FIG. 1.

A primary BOP 212 a and a secondary BOP 212 b are also provided aboutcorresponding wellbores 214 a,b. The wellbores 214 a,b extend into areservoir 202 for passing fluids therefrom. The primary and secondaryBOPs 212 a,b may operate in the same manner as the BOP 112 previouslydescribed herein. A primary manifold 216 a and a secondary manifold 216b are also operatively connected to primary BOP 212 a and secondary BOP212 b, respectively. The primary and secondary manifolds 216 a,b mayoperate in the same manner as the manifold 116 previously describedherein. As shown, the primary and secondary BOPS 212 a,b and the primaryand secondary manifolds 216 a,b are operatively connected to the risers206 a and 206 b.

The primary structure 200 a is configured to produce fluids from subseareservoir 202 through one or both wellbores 214 a,b. Optionally, one ormore wellbores 214 a,b may be provided to produce fluids from subseareservoir 202. The BOPs 212 a,b and/or manifolds 216 a,b may be fluidlyconnected via primary flowlines 234 a-d to buoyant riser 206 a to pumpfluid from reservoir 202 thereto. Pump 218 a and manifolds 216 a,b maybe selectively activated to manipulate flow into riser 206 a. Fluidreceived in riser 206 a may be passed to collector 222 a, and on tovessels 220 a,b for transport.

Optionally, a secondary structure 200 b may be provided to transport atleast a portion of the fluid to the surface. This configuration providesan additional structure for transporting the fluid, thereby increasingflow volume and/or rate capabilities and/or flexibility regardingdowntime and maintenance. This configuration also provides analternative wellsite for transporting fluids to the surface, should theprimary structure 200 a be unavailable, for example, due to bad weatheror malfunction.

The primary and/or secondary structure may be provided with a container236 at a subsea end of the buoyant riser 206 b. The container 236 ispreferably positioned about the riser 206 b above trap 217 b. Container236 may be a frusto-conically shaped container configured to receivehigh pressure fluid. The container 236 may be fluidly connected tovarious conduits about secondary structure 200 b for receiving fluidtherefrom. As schematically depicted in FIG. 2, secondary structure 200b is fluidly connected via secondary flowlines 238 a-d to BOPs 212 a,band/or manifolds 216 a,b. A pump 218 b may be used to draw fluid intothe riser 206 b through the flowlines 238 a-d. Valving (not shown) mayoptionally be provided in secondary flowlines 238 a-d to control flowinto the container 236.

Pumps 218 a,b may be used to draw fluid into the buoyant risers 206 a,bfor transport to the surface. The buoyant risers 206 a,b may beconventional risers or tubing used to carry fluid to the surface. Insome embodiments, buoyant risers 206 a,b are provided with buoyancymodules 239 a,b, respectively, for maintaining position andfunctionality of the buoyant risers 206 a,b in the sea 203,alternatively, or in addition, a platform (not shown) may be used toprovide buoyancy.

As shown in FIG. 2, the buoyant risers 206 a,b are ‘free standing,’ orseparate from the BOPs 212 a,b. However, in some configurations, one orboth of the buoyant risers 206 a,b may be positioned about or connectedto the BOPs 212 a,b. The buoyant risers 206 a,b may optionally beprovided with devices, such as clean out ports 240 a,b, for performingvarious functions. One or more chokes (not shown) may also be providedin the riser for controlling flow therethrough. While a conventionalriser may be used, various other risers with advanced capabilities maybe used as will be described further herein.

A surface end of the risers 206 a,b may be connected to collectors 222a,b for passing fluid thereto. The collectors 222 a,b may beconventional collectors capable of storing fluid at or near the surface.Part of all of the collectors 222 a,b are preferably towable and/orsubmergeable as needed. For example, in bad weather, it may be desirableto transport the collectors 222 a,b to another location, or submerge thecollectors 222 a,b a distance below sea level. Preferably, the collectormay be submerged a distance (e.g., about 50-100 m below sea level) toavoid waves and/or to provide stability.

As shown in FIG. 2, each collector 222 a,b is preferably operativelyconnectable to the risers 206 a,b for receiving high pressure fluidstherefrom. The collectors 222 a,b may be positioned in a floatingplatform (or boom) 242 a,b. The collectors 222 a,b are preferablycapable of storing the fluids at a desired pressure at or below sealevel. Preferably, the collectors 222 a,b separate the fluids receivedinto components, such as gases and liquids. One or more flares 224 a,bmay be positioned above the collectors 222 a,b for burning separated gasand/or oil. A flare tube may extend from collectors 222 a,b to the flarefor passing the fluid to be burned thereto, as will be described morefully herein. The remaining fluids may be stored in the collector 222a,b, or released therefrom for transport.

Preferably, the pressure of the fluid received from the collectors 222a,b is reduced during separation and burning. The collector ispreferable capable of operating from about 350 kPa to about 1750 KPa, orfrom about 700 KPa to about 1000 KPa. A choke 225 a,b may be provided tocontrol the pressure of the liquid in the collectors. Each collector 222a,b may be fluidly connected to the vessel 220 a via tubing 226 a,b forpassing fluid thereto. The tubing 226 may be a low pressure hose capableof floating at the surface. One or more tubings 226 may be positionedbetween one or more of the collectors 222 a,b and/or vessels 220 a,b.Preferably, the tubing 226 obviates the need for a high pressure swivelor other pressure reduction devices.

As shown, multiple vessels 220 a,b may be used in connection with theprimary and/or secondary structure 200 a,b. Preferably, vessel orvessels 220 a,b have sufficient volume to enable transport at highrates. The vessels 220 a,b may be selectively connected to one or morestructures 200 a,b via the tubing 226 a,b for receiving fluid therefrom.The vessels may be, for example, a tanker, an FPSO, a shuttle tanker, awork boat such as a remote operated vehicle (ROV) (or communications)boat, or other transporter capable of performing operations for thewellsite. Vessel 220 a may be provided with an additional collector 222c for further separating the fluids received therein, and a flare 224 cfor burning gas from these fluids. Vessel 220 a may then be connected toa pipeline, or periodically offload liquids to another vessel or storagecontainer.

Vessel 220 a may be capable of storing and/or transporting fluids fromthe collectors 222 a,b. The vessel 220 a may be, for example, aconventional offloading shuttle tanker. Vessel 220 b may be operativelyconnectable to the manifold 216 a or other equipment via an umbilical234 for passing communication and/or power signals therebetween, forexample by controlling an ROV. The vessel 220 b may be capable ofdeploying an ROV (not shown) for performing various functions about thestructures 200 a,b as will be understood by one of skill in the art.Preferably, vessel 220 b is provided with electronics 227, such ascontrollers, processors or other devices, for operating the ROV and/orone or more components at the wellsite. The electronics 227 may furtherinclude communication systems, such as transceivers, for communicationwith the components of the structures 200 a,b and/or with offsitelocations.

In the event that a leak 230 occurs through one or both BOPs 212 a,b, acontaining system or subsea collector, such as cap 232 a, may beprovided. The cap 232 a may be connected to the BOP 212 a for capturingfluid leaking therefrom. The cap 232 a is positioned directly over theBOP 212 a to create a seal thereon to prevent release of the fluid intothe sea 203. The cap 232 a may be fluidly connected via flowline 234 ato the manifold 216 a for passing fluid thereto. Optionally, the cap 232a may be fluidly connected to other components about the structures 200a,b, such as riser 206 a, collector 222 a and/or vessels 220 a,b.

In the event a cap 232 a cannot be directly sealed to the BOP, then afunnel may be used. The funnel 232 b is positioned above the BOP 212 bfor capturing fluid leaking therefrom. The funnel 232 b may have acylindrical body with an open bottom and a tapered top. In oneembodiment, the funnel 232 b may be positioned over the BOP 212 b tocreate a seal thereon or forced into the mud or sea bottom to create aseal and to prevent release of the fluid into the sea 203. In anotherembodiment, the funnel 232 b may be a non-sealed, open water capallowing free passage of sea water into and out of the funnel. Thefunnel 232 b may be fluidly connected via flowline 234 d to the manifold216 b for passing fluid thereto. Optionally, the funnel 232 b may befluidly connected to other components about the structures 200 a,b, suchas riser 206 a,b, collector 222 a,b and/or vessels 220 a,b.

Various features may be provided in the funnel 232 b, such as collectorvalves 250 to control flow, gauge (or fluid indicator) 252 to measurefluid parameters, and clump weights 254 or pilings with tethers tosecure the funnel 232 b in position on sea floor 210. A pump indicator256 may also be connected between the funnel 232 b and the manifold 216b or pump 218 a to gauge fluid parameters, such as pressure, flow ratesand temperature. Similar features may also be provided in cap 232 a.

FIGS. 3A & 3B:

FIGS. 3A and 3B are schematic diagrams depicting a riser 306 usable withthe subsea containment systems of FIGS. 1 and/or 2. The riser may beconfigured to provide high rate separation of fluids, for example toreduce gas handling and/or fluid pressure. The riser 306 is operativelyconnected to a suction pile 308 via riser connector 380 at a subsea end360. A surface end 362 of the riser 306 is positionable at the surfaceadjacent, for example, collector 122,222 of FIGS. 1 and/or 2. As shownin FIG. 3, the riser 306 is a straight, vertical tube for passing fluidtherethrough, but may optionally be of another configuration or angle.

The riser 306 of FIG. 3 comprises a tubular portion 370, an intakeportion 372, a buoyancy portion 374, a separator portion 376 and a flareportion 378. The intake portion 372 may be provided with, for example, apump 118 a,b as shown in FIG. 2 for drawing fluid into the riser 306.The intake portion 372 receives fluid and passes it through the tubularportion 370. The tubular portion extends from the intake portion 372 tothe separator portion 376 for passing fluid therethrough. The buoyancyportion 374 preferably has a float or other member to provide buoyancysupport to the riser 306. The buoyancy portion 374 may be integral withthe tubular portion 370, or separate therefrom, for example, on an outersurface thereof.

Separator portion 376 is connected to the tubular portion 370 forseparating fluid passing therethrough. The separator portion 376 ispositionable in fluid communication with the tubular portion 370 forreceiving fluid therefrom, and separating such fluid into components,such as gas and liquid. The separator portion 376 preferably passes agas portion of the fluid to the flare portion 378 to be burned off. Theflare portion 378 may comprise a flare pipe for transferring the gas tothe flare (see, e.g., flares 124, 224 a,b of FIGS. 1 and 2). Theseparator portion 376 also preferably passes a fluid portion out to astorage and/or transport facility, such as vessel 220 a,b and/orcollector 222 a,b of FIG. 2.

The separator portion 376 comprises an integrated separator 377 as shownin greater detail in FIG. 3B. FIG. 3B is a schematic view of anintegrated separator 377 usable with the riser 306 of FIG. 3A. Theintegrated separator 377 is preferably capable of separating componentsof the fluid into, for example, gas and liquid. The integrated separator377 comprises upper and lower central tubes 379 a,b fluidly connected toseparator tanks 381. The central tubes 379 a,b are in fluidcommunication with tubular portion 370 for receiving fluid therefrom.The lower central tube 379 a may have a smaller diameter than the uppercentral tube 379 b. Fluid passing into the lower and upper central tubes379 a,b passes into the separator tanks 381. Each of the separator tanks381 has a separator valve 384 to facilitate separation of the componentsof the fluid. The separation valves 384 may be, for example, aperforated plate, a series of plates that allow fluid passagetherethrough, or a centrifugal member that rotationally separates thefluid. Preferably, separation occurs at a high rate of speed as thefluid flows through the integrated separator 377, and provides thedesired separation and pressure of the fluid. Gas may be passed from gasoutlets 383 to flare pipe 378 and/or liquid may be passed from liquidoutlets 385 to the collectors 222 a,b and/or vessels 220 a,b as shown inFIG. 2.

Once separated, the gas components may be passed from the integratedseparator 377 to the flare portion 378 for burning, and the liquidcomponents diverted out of the integrated separator 377 to a desiredlocation for storage and/or transport. The fluid components may bediverted, for example, to collector 122, collectors 222 a,b and/orvessels 120, 220 a,b as shown in FIGS. 1 and 2. Flowlines and otherdevices (not shown) may be provided for transferring the fluids from theintegrated separator 377.

Additional separation capabilities may be provided within the integratedseparator 377 and/or riser 306 and/or separate therefrom. For example,an integrated separator 377 may also be incorporated in other portionsof the riser 306, such as the buoyancy portion 374. The buoyancy portion374 may be used to provide a first stage of separation to the fluidprior to passing through the separator portion 376 for furtherseparation. Additional separation may be provided by other devices, suchas the collectors 222 a,b of FIG. 2.

Suitable separators for use with the invention are disclosed in U.K.Patent Publication GB1397863, and U.S. Pat. No. 3,988,132; which areherein incorporated by reference in their entirety.

FIG. 4:

FIG. 4 is a flow chart depicting a method 400 of deepwater containment.The method involves passing (487) a fluid from the reservoir (e.g., 102,202) to a surface collector (e.g., 122, 222 a,b) via a riser (106, 206a,b, 306) of a primary structure (e.g., 200 a). The method 400 mayoptionally involve selectively (488) diverting at least a portion of thefluid from the primary structure (e.g., 200 a) to a container (e.g.,236) of a secondary structure (e.g., 200 b). Like the primary structure,fluid may be passed (489) from the reservoir (e.g., 102, 202) to asurface collector (e.g., 122, 222 a,b) via a riser (e.g., 106, 206 a,b,306) of the secondary structure (e.g., 200 a). Fluid may be separated(490) as the fluid passes through the riser (e.g., 106, 206 a,b, 306).

The fluid may be selectively pumped (491) from the reservoir (e.g., 102,202) to the riser (e.g., 106, 206 a,b, 306) via a BOP (e.g., 112, 212a,b). The fluid passed to the riser may be stored (492) in the surfacecollector (e.g., 122, 222 a,b). The fluid may be separated (493) in thesurface collector (e.g., 122, 222 a,b). At least a portion of the fluidmay be burned (494) using a flare (e.g., 124, 224 a,b,c).

At least a portion of the fluid may be transferred (495) from thesurface collector (e.g., 122, 222 a,b) to at least one vessel (e.g.,120, 220 a,b). The vessel may be provided with an ROV. In such cases, anROV may be deployed (496) from the vessel (e.g., 220 b) to the structure(e.g., 200 a,b) for performing wellsite tasks. A collector (e.g., 222 c)may be provided on the vessel so that the fluid may be separated (497)in the at least one vessel (e.g., 220 a,b).

If a leak occurs from the BOP, fluid may be captured (498) from the BOP(e.g., 112, 212 a,b) via a subsea collector (e.g., 232 a,b). Thecaptured fluid may be passed (499) from the subsea collector (e.g., 232a,b) to the riser (e.g., 106, 206 a,b), and on to the surface.Additional steps may be performed, such as measuring fluid parameters,towing the surface collector (e.g., 122, 222 a,b), or passing the fluidthrough a manifold (e.g., 116, 216 a,b). The steps of the method may beperformed in any order, and repeated as desired.

Illustrative Embodiments

In one embodiment, there is disclosed an oil and gas collection system,comprising a source of oil and gas flowing into a body of water; acollector located adjacent the source of oil and gas; a riser totransport the oil and gas towards a surface of the body of water, afirst end of the riser fluidly connected to the collector; and aseparator fluidly connected to a second end of the riser, the separatoradapted to separate the oil and gas into a first oil rich stream and asecond gas rich stream, the separator comprising an oil rich streamoutlet and a gas rich stream outlet. In some embodiments, the source ofoil and gas comprises a blow out preventer. In some embodiments, thecollector is sealed to the source of oil and gas. In some embodiments,the collector is open to the source of oil and gas and the body ofwater. In some embodiments, the collector comprises a containment dome.In some embodiments, the riser is anchored to a sea floor beneath thebody of water. In some embodiments, the riser is anchored to a sea floorwith a suction pile driven into the sea floor. In some embodiments, thesystem also includes a manifold located between the collector and theriser. In some embodiments, the system also includes a plurality ofhoses connected the manifold with the first end of the riser, where themanifold may include a valve connected to each of the hoses. In someembodiments, the system also includes a pump with an outlet feeding intothe first end of the riser. In some embodiments, the separator providesbuoyancy to the riser. In some embodiments, the separator is floating ona surface of the body of water. In some embodiments, the separator issubmerged a distance beneath a surface of the body of water, for examplefrom about 50 meters to about 250 meters. In some embodiments, theseparator is operating at a pressure from about 50 to about 250 psi. Insome embodiments, the system also includes a flare at a surface of thebody of water, the flare fluidly connected the gas rich stream outlet.In some embodiments, the system also includes a trap at a first end ofthe riser, the trap comprising an access port for cleaning out the trap.In some embodiments, the system also includes a vessel floating on asurface of the body of water, the vessel fluidly connected the oil richstream outlet. In some embodiments, the oil rich stream comprises aportion of gas, the vessel further comprising a separator to separatethe portion of gas from the oil. In some embodiments, the separator onthe vessel is a low pressure separator, for example operating a pressureless than about 50 psi. In some embodiments, the vessel furthercomprises a flare adapted to burn the portion of gas. In someembodiments, the system also includes a second riser to transport theoil and gas towards a surface of the body of water, a first end of theriser fluidly connected to the collector; and a second separator fluidlyconnected to a second end of the riser, the separator adapted toseparate the oil and gas into a first oil rich stream and a second gasrich stream, the separator comprising an oil rich stream outlet and agas rich stream outlet.

In one embodiment, there is disclosed a method comprising locating asource of oil and gas flowing into a body of water; collecting at leasta portion of the oil and gas; flowing the collected oil and gas to asurface of the body of water; separating at least a portion of the oilfrom the gas; flowing the portion of oil to a floating vessel; andburning at least a portion of the gas.

It will be understood from the foregoing description that variousmodifications and changes may be made in the preferred and alternativeembodiments of the present invention without departing from its truespirit. For example, one or more wellsites and/or components thereof(e.g., collectors, vessels, BOPS, risers, etc.) may be positioned aboutthe reservoir for producing fluids and/or containing leaks.

This description is intended for purposes of illustration only andshould not be construed in a limiting sense. The scope of this inventionshould be determined only by the language of the claims that follow. Theterm “comprising” within the claims is intended to mean “including atleast” such that the recited listing of elements in a claim are an opengroup. “A,” “an” and other singular terms are intended to include theplural forms thereof unless specifically excluded.

1. An oil and gas collection system, comprising: a source of oil and gasflowing into a body of water; a collector located adjacent the source ofoil and gas; a riser to transport the oil and gas towards a surface ofthe body of water, a first end of the riser fluidly connected to thecollector; and a separator fluidly connected to a second end of theriser, the separator adapted to separate the oil and gas into a firstoil rich stream and a second gas rich stream, the separator comprisingan oil rich stream outlet and a gas rich stream outlet.
 2. The system ofclaim 1, wherein the source of oil and gas comprises a blow outpreventer.
 3. The system of claim 1, wherein the collector is sealed tothe source of oil and gas.
 4. The system of claim 1, wherein thecollector is open to the source of oil and gas and the body of water. 5.The system of claim 1, wherein the collector comprises a containmentdome.
 6. The system of claim 1, wherein the riser is anchored to a seafloor beneath the body of water.
 7. The system of claim 1, wherein theriser is anchored to a sea floor with a suction pile driven into the seafloor.
 8. The system of claim 1, further comprising a manifold locatedbetween the collector and the riser.
 9. The system of claim 1, furthercomprising a pump with an outlet feeding into the first end of theriser.
 10. The system of claim 1, wherein the separator providesbuoyancy to the riser.
 11. The system of claim 1, wherein the separatoris floating on a surface of the body of water.
 12. The system of claim1, wherein the separator is submerged a distance beneath a surface ofthe body of water, for example from about 50 meters to about 250 meters.13. The system of claim 1, wherein the separator is operating at apressure from about 50 to about 250 psi.
 14. The system of claim 1,further comprising a flare at a surface of the body of water, the flarefluidly connected the gas rich stream outlet.
 15. The system of claim 1,further comprising a trap at a first end of the riser, the trapcomprising an access port for cleaning out the trap.
 16. The system ofclaim 1, further comprising a vessel floating on a surface of the bodyof water, the vessel fluidly connected the oil rich stream outlet. 17.The system of claim 1, wherein the oil rich stream comprises a portionof gas, the vessel further comprising a separator to separate theportion of gas from the oil.
 18. The system of claim 17, wherein theseparator on the vessel is a low pressure separator, for exampleoperating a pressure less than about 50 psi.
 19. The system of claim 17,wherein the vessel further comprises a flare adapted to burn the portionof gas.
 20. The system of claim 1, further comprising: a second riser totransport the oil and gas towards a surface of the body of water, afirst end of the riser fluidly connected to the collector; and a secondseparator fluidly connected to a second end of the riser, the separatoradapted to separate the oil and gas into a first oil rich stream and asecond gas rich stream, the separator comprising an oil rich streamoutlet and a gas rich stream outlet.
 21. A method comprising: locating asource of oil and gas flowing into a body of water; collecting at leasta portion of the oil and gas; flowing the collected oil and gas to asurface of the body of water; separating at least a portion of the oilfrom the gas; flowing the portion of oil to a floating vessel; andburning at least a portion of the gas.